Date: Sun, 29 Nov 2015 10:21:50 -0800
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>, netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        syzkaller <syzkaller@googlegroups.com>,
        Kostya Serebryany <kcc@google.com>,
        Alexander Potapenko <glider@google.com>,
        Eric Dumazet <edumazet@google.com>,
        Sasha Levin <sasha.levin@oracle.com>, daniel@iogearbox.net
Subject: Re: user-controllable kmalloc size in bpf syscall
Message-ID: <20151129182149.GA79352@ast-mbp.thefacebook.com>
References: <CACT4Y+b1k7Ofvn6xa=qWv9xP6BbteWOnZsJMXLZ=GOby-ajF=w@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CACT4Y+b1k7Ofvn6xa=qWv9xP6BbteWOnZsJMXLZ=GOby-ajF=w@mail.gmail.com>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 685
Lines: 18

On Sun, Nov 29, 2015 at 02:18:29PM +0100, Dmitry Vyukov wrote:
>         ca.key_size = 1;
>         ca.value_size = 0xfffffff9;
>         ca.max_entries = 10;
>         int fd = syscall(SYS_bpf, BPF_MAP_CREATE, &ca, sizeof(ca));
...
> ------------[ cut here ]------------
> WARNING: CPU: 2 PID: 11122 at mm/page_alloc.c:2989
> __alloc_pages_nodemask+0x695/0x14e0()

thanks for the report. That's an integer overflow :(
working on the fix.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/